RU2071034C1 - Navigational complex - Google Patents

Abstract

FIELD: navigation. SUBSTANCE: navigational complex includes equipment of satellite navigational system User, sensors of roll angles, attack and slide, three-step heading mounted in fixed in-the-earth coordinate system and airborne computer manufactured for joint processing of signals from all pickups. Complex may also has sensors of linear accelerations and angular speeds. EFFECT: enhanced operating reliability and precision. 2 cl, 3 dwg

Description

 The invention relates to navigation. It can be used to improve the accuracy of determining the current coordinates and spatial angles - the course and pitch of aircraft. The tasks of increasing the accuracy of determining the current coordinates of the aircraft arise when the aircraft is brought to a point with the specified coordinates to the start of the runway, during aerial photography to improve the accuracy of the current location of aerial photographs to the terrain and a number of other cases.

 An analogue of the invention, on the one hand, can be a navigation system [2] in which the ground-based radio navigation system is used to periodically correct a magnetic direction sensor (MDN) using the horizontal component of the Earth’s magnetic field.

 On the other hand, the analogue and prototype of the invention, in which high accuracy of navigation measurements is achieved by combining (joint processing) of signals from navigation sensors (subsystems) in the computer of the navigation complex of the NK, are widely used NK [1] consisting of satellite consumer equipment navigation system AP SNA [1,3] and spatial orientation system in the form of a strapdown inertial navigation system BINS [1, 3, 5, 6], in turn, consisting of precision idrometricheskoy GMR system, and a precision accelerometer AMC system mounted on the aircraft in the coupled system of coordinates, and a calculator, in which the signals of said interconnecting subsystems. The main disadvantages of ANN equipment are its bulkiness, high cost and complexity in operation.

При F(p) 1/(1 + Тр) (2)
Y(p) = X(p)+1/(1+Tp)δ₁+Tp/(1+Tp)δ₂ (3)
На фиг.1 обозначено: 1 измеритель 1 с ошибкой с широкополосным спектром, 2 измеритель 2 с ошибкой с узкополосным спектром, 3 сигнал X+δ₁, 4 сигнал X+δ₂, 5 фильтр с передаточной функцией F(p) 1/(1 + Tp), 6 - сигнал Y на выходе устройства.An increase in the accuracy of navigation measurements is obtained due to the integration of navigation subsystems that are different according to the operating principles included in the navigation complex of the NK [1, 5, 6] Under the integration of two or more sensors, the combined processing of their signals is raised in such a way as to reduce measurement errors. Figure 1 shows a diagram of the simplest example of the integration of two meters, which is described by the following expressions

For F (p) 1 / (1 + Tr) (2)
Y (p) = X (p) + 1 / (1 + Tp) δ ₁ + Tp / (1 + Tp) δ ₂ (3)
Figure 1 indicates: 1 meter 1 with an error with a broadband spectrum, 2 meter 2 with an error with a narrowband spectrum, 3 signal X + δ ₁ , 4 signal X + δ ₂ , 5 filter with a transfer function F (p) 1 / ( 1 + Tp), 6 - signal Y at the output of the device.

 The above calculations show that if the error spectrum of the first sensor has a wide band and the second is narrow, then the output of the processing system (filter) will have attenuation of both components of the error. The greatest gain from integration is obtained with a small intersection of the energy spectra of the errors of these meters.

 The purpose of the invention is the accurate determination of the current coordinates and spatial angles of the aircraft due to the integration [1, 5, 6, 7] in the calculator of the NK signals from the AP SNA with signals from the spatial orientation system, consisting of relatively simple and inexpensive aviation sensors: three-stage MDS, angle sensors roll and pitch and air sensors of angles of attack and slip.

 AP SNA (GLONASS and NAVSTAR systems) allows you to determine the current coordinates and components of the velocity vector of the aircraft in the Earth's coordinate system [4] The error spectrum of AP SNA occupies a fairly wide frequency band.

 The Earth’s magnetic field rotates together with the planet’s surface, so there will be no precession errors that are in the ANN and associated with the Earth’s rotation in such a system. However, due to the movement of the aircraft along the earth's surface, the position of the magnetic vector (declination and inclination angles) will slowly change. The spectra of errors associated with a change in these angles and with a change in the drift angle of the aircraft, caused by a change in the constant component of the wind speed, are rather narrow.

 The pitch and yaw angles can be calculated, respectively, as the sum of the angles of attack and slip with the angles of the vertical and horizontal components of the velocity vector of the aircraft, as measured by the AP of the SNA. Since the error spectra of measuring the AP of the SNA and the sensors of the angle of attack and slip are quite wide, the calculated values of the pitch and yaw angles will have an error with a wide spectrum band.

 The signals measured by the roll and pitch sensors, which are usually gyroscopic sensors, have very low frequency error spectra.

 The essence of the invention lies in the fact that, in contrast to a spacecraft with an ANN, in which the spatial angles of the aircraft are counted relative to the inertial axes of space, the present invention proposes the spatial angles of the aircraft to be counted from the base determined by the signals of the three-degree MDS, which measures the components of the Earth’s magnetic field, and signals of pitch angle sensors, roll.

 In order to unambiguously determine the position of the coordinate axes of an aircraft in space during flights in the mid-latitude region, it is sufficient to know one of the aircraft’s spatial angles (pitch or roll) in addition to the declination and inclination of the Earth’s magnetic field vector. But when flying in the equatorial zone, the direction of the axis of the sensor of the spatial angle of the aircraft can coincide with the direction of the vector of the Earth's magnetic field. In this case, the accuracy of coordinate measurement will drop sharply. Such a problem will not arise if the ND calculator introduces the largest in deviation from the axis of the MPF vector angles of roll or pitch of the aircraft, continuously measured by the respective sensors.

 For small periods of time, due to a wide range of errors, the accuracy of navigation measurements in the NK is not high. In order to increase the accuracy of measuring the current values of the coordinates and spatial angles of the aircraft, by combining the signals in the computer NK, the composition of the NK for complexing in the computer are entered installed on the aircraft in a connected coordinate system, sensors of linear accelerations of the DLD and angular velocities of the TLS having relatively narrow spectra mistakes.

 The scheme of the proposed device for accurate measurement of the parameters of the aircraft is shown in figure 2. The onboard computer NK 1 receives signals of the magnitude of the components of the Earth’s magnetic field vector, measured by the three-degree MDN 2, installed in the zone of small influence of magnetic masses on the aircraft in a coupled coordinate system, roll angle sensors 3 and aircraft pitch 4 and angle of attack sensors 8 and slip 9. From the AP SNA 5, signals are received about the coordinates of the aircraft 6 and the components of its velocity vector 7. To increase the accuracy of measuring the current values of the coordinates, speeds and spatial angles of the aircraft over small periods of time in the composition of the SC (DL) 10 and angular velocities (TLS) ) 11 mounted on the aircraft in a connected coordinate system. Based on the data received from the systems and sensors mentioned above, the exact values of pitch angles (12), roll (13) and yaw (14), as well as the exact values of coordinates (15) and components of the velocity vector 16 LA are calculated in the calculator based on aggregation . To reduce the time of transient processes, the initial values of coordinates and angles from the remote control 17 are entered into the computer before starting.

Figure 3 shows the structural seme of the program of the calculator. The choice of configuration and parameters of the calculator, providing a reduction of errors in navigation measurements due to the integration of joint processing — the signals coming from the navigation subsystems included in the navigation complex and individual sensors, is achieved through the implementation of the algorithm for combining signals in the calculator [6, 7] Figure 3 indicates :
1 magnetic direction sensor;
2 calculator of the angles of inclination and declination in a connected coordinate system;
3 pitch and roll angle sensor;
4 calculator of the angles of inclination, declination and yaw (magnetic) in the earth's coordinate system;
5 filter, combining the signals of the sensors of the angles of attack, slip, roll, yaw and pitch with the signals of the satellite navigation system;
6 filter, combining the signals of the coordinates and speed of the aircraft with the signals of the sensors of linear accelerations;
7 filter that combines signals of spatial angles with signals of angular velocity sensors;
8 consumer equipment of satellite navigation system;
9 sensors of angles of attack and slip;
10 signals of a magnetic direction sensor;
11 signals of the angles of declination and inclination;
12 tilt and pitch angle signals;
13 signals of roll angles, pitch, yaw and declination and inclination angles in the earth coordinate system;
14 corrections to the angles of declination and inclination in the earth's coordinate system;
15 signals of coordinates and speed of the aircraft after integration;
16 signals of roll angles, pitch, yaw;
17 signals of linear acceleration sensors;
18 signals of sensors of angles of speeds;
19 signals of the coordinates and speed of the aircraft from the consumer equipment of the satellite navigation system;
20 signals of sensors of angles of attack and slip;
21 accurate signals of coordinates and speed of the aircraft;
22 accurate angle signals of roll, pitch, yaw.

 In addition to the parametric optimization of the complexing algorithm [6, 7], an optimal complexing algorithm can be implemented that provides the minimum norm of the error vector, which is calculated using optimal filtering methods [1, 5], taking into account the observation vector of the mathematical model of sensor errors and the communication equations ( generally nonlinear) between sensors.

 When entering the initial (starting) values of coordinates and angles, the optimal filter algorithm that determines the signal processing program in the computer can have a structure with constant parameters.

LITERATURE
[1] Babich O.A. Information processing in navigation systems. M. Engineering, 1991.

 [2] Application France 2614694. Publ. 11/04/88.

 [3] US Patent 4,743,914. Publ. 05/10/08.

 [4] Aeronautical Radio Navigation: A Handbook. Ed. A.A. Sosnovsky. - M. Transport, 1990.

 [5] Rivkin S.S. et al. Statistical optimization of navigation systems. - L. Shipbuilding, 1976.

 [6] Chelpanov IB Optimal signal processing in navigation systems. M. Science, 1967.

 [7] Bobnev M.P. Krivitsky B.Kh. Yarlykov M.S. Integrated radio automation systems. M. Sov. radio, 1968.

Claims (2)

 1. The navigation system of the aircraft, consisting of consumer equipment of the satellite navigation system, roll angle sensors, pitch and on-board computer, configured to jointly process signals from the consumer equipment of the satellite navigation system and roll and pitch sensors, characterized in that it is additionally introduced a three-degree magnetic direction sensor installed in the associated coordinate system of the aircraft, angle of attack and slip sensors, with the numerator is adapted to joint processing of signals from all sensors.  2. The aircraft navigation system according to claim 1, characterized in that linear acceleration and angular velocity sensors installed in the aircraft’s associated coordinate system are additionally introduced into it, and the on-board computer is capable of processing signals from all sensors together.

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